For actions an AI agent or bot could do, as opposed to more AI-generated or assisted features/code, what about something to automate common/trivial janny actions that don't particularly require much in the way of judgement, just known action in known conditions.
I am thinking something like merging multiple posts, correcting un-thumbnailed images, and similiar.
Let us say someone multi-posts instead updating their post within the edit window. Either in the report dropdown or another one, there are auto-janny actions, amongst which would be a "merge multi-posts." For more sophistication, depending on the age of the account or other factors JannyBot could take additional acitons. For new accounts, JannyBot might send them a DM with instructions on how to use the edit feature. With older accounts that should know better, JannyBot might look at the timestamps to see if the user was struggling against the site being unresponsive via various metrics (known DDOS during that time, multiple duplicate or near duplicate posts in a short time period), or just lazy (different content, more spread out during the edit window, and just silently auto-merge the posts or additionally leave a comment calling the user a lazy nigger, as appropriate.
Another action might be auto archiving unarchived links, which seem to be on the rise over the past couple years. Within the post editor, one might click the auto-archive function, and have links auto-inserted to ArchiveToday, Ghost Archive, Wayback Machine, Megalodon.jp, etc for each link in their post. Within a thread, one could select auto-archive as a JannyBot action. Again, new accounts might get DMs from JannyBot on how to archive links, and older accounts have JannyBot editing in a comment that the user is a lazy nigger. Perhaps repeat offenders might wind up with all links on the enitre site magically redirect to the Archive Tools thread for just that one user for a short while. If someone tries to abuse the auto-archive function on posts that were already well archived, then JannyBot leaves edits a comment on that user's next post in the thread calling that user a faggot who tried to abuse the auto-janny functions.
Your own jannies probably have a better idea of what actions could be automated by an agentic janny.
Edit: more ideas
Someone files a report or Talk to Staff that a user is following them around the forum, negrating all of their posts, even in threads where the sticker-applying user does not normally post or interact. JannyBot confirms the sticker-stalking, and suspends both user's sticker privileges for the nest 24 hours, or perhaps sticker-bans the abuser, and edits a comment into the reporting user's next post that the reporting user is a little bitch who cares too much about stickers.
Something perhaps useful to you to help you better protect us retards from demons like Brickface: An agent analyzes the connection logs for various users to see who's consistently connecting from a residential or business IP address instead of a known VPN address or tor exit node, and DM's those users that they've been detected not using VPNs or Tor, and includes links on how to get VPNs or use Tor.